JP2005243852A - Power conversion apparatus - Google Patents

Power conversion apparatus Download PDF

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JP2005243852A
JP2005243852A JP2004050558A JP2004050558A JP2005243852A JP 2005243852 A JP2005243852 A JP 2005243852A JP 2004050558 A JP2004050558 A JP 2004050558A JP 2004050558 A JP2004050558 A JP 2004050558A JP 2005243852 A JP2005243852 A JP 2005243852A
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power
solar cell
cell panel
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voltage
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Taneo Higuchi
種男 樋口
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Kyocera Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a power conversion apparatus wherein it has a fast control speed, a response speed will not deteriorate, even when no solar insolation is varied, without requiring the need of the installation of an expensive illuminance meter, it can operate with accurate maximum output voltage even when a solar cell panel suffers from the lowering of an output owing to outer factors, such as the shade, and further it can effectively follow a maximum output power point of a DC power supply composed of the solar cell panel. <P>SOLUTION: The power conversion apparatus comprises output control means for controlling the output voltage of the solar cell panel to make output power of the solar cell panel maximum and an image element for detecting a change of illuminance around the solar cell panel. The image element detects the change of illuminance around the solar cell panel. The output control means, when there is a change in illuminance, controls the operation such that the output power of the solar cell panel does not change to keep the output power of the solar cell panel maximum. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、太陽電池パネル等の直流電源から得られる直流電力を交流電力に変換する電力変換装置に関し、特に太陽電池パネルの発電電力の最大出力点を追尾する電力変換装置に関するものである。   The present invention relates to a power converter that converts DC power obtained from a DC power source such as a solar battery panel into AC power, and more particularly to a power converter that tracks the maximum output point of the generated power of a solar battery panel.

近年、太陽エネルギーを電気エネルギーへ光電変換できる太陽電池パネルが発電し、出力する直流電力をインバータにて交流電力に変換し、太陽電池パネルを商用電力系統と連系する系統連系システムが実用化されている。   In recent years, a grid-connected system that generates power from a solar cell panel that can photoelectrically convert solar energy into electrical energy, converts the output DC power to AC power using an inverter, and links the solar cell panel to a commercial power system has been put into practical use. Has been.

図５は従来の系統連系システムの形態を示す概略説明図である。   FIG. 5 is a schematic explanatory diagram showing a form of a conventional grid interconnection system.

図５に示すように、この系統連系システムにおいては、太陽電池パネルにより構成された直流電源２にて発電した直流電力は、電力変換装置１にてたとえば２００Ｖの交流電力に変換され、商用電力系統１６と連系運転されている。従来より、太陽電池パネルの出力する直流電力をインバータにて交流電力に変換させる電力変換装置においては、太陽電池パネルにより構成された直流電源の出力を効率よく取り出すために最大出力電力点を追尾させるＭＰＰＴ（最大電力追従制御 Ｍｕｘｉｍｕｍ Ｐｏｗｅｒ Ｐｏｉｎｔ Ｔｒａｃｋｅｒ）制御が行われている。   As shown in FIG. 5, in this grid interconnection system, the DC power generated by the DC power source 2 constituted by the solar cell panel is converted into, for example, 200V AC power by the power converter 1, and commercial power The system 16 is connected to the grid 16. Conventionally, in a power conversion device that converts DC power output from a solar cell panel into AC power by an inverter, the maximum output power point is tracked in order to efficiently extract the output of the DC power source configured by the solar cell panel. MPPT (Maximum Power Tracking Control) control is performed.

図６は従来の電力変換装置の形態を示す一例の説明図、図７は従来の太陽電池パネルにより構成された直流電源の電圧−電流特性を示す概略グラフ、図８は従来の太陽電池パネルにより構成された直流電源の電圧−電力特性を示す概略グラフである。   FIG. 6 is an explanatory diagram of an example showing the form of a conventional power conversion device, FIG. 7 is a schematic graph showing the voltage-current characteristics of a DC power source constituted by a conventional solar cell panel, and FIG. 8 is an illustration of the conventional solar cell panel. It is a schematic graph which shows the voltage-power characteristic of the comprised DC power supply.

一般に電力変換装置１は、図６に示すように、太陽電池パネルにより構成された直流電源２と、この直流電源２の出力電圧を異なる電圧に変換する直流電圧変換回路３と、直流電圧変換回路３にて変換された直流電力を交流電力に変換するインバータ回路４とから構成され、太陽電池パネルにより構成された直流電源２の出力電圧検出手段１０と出力電流検出手段１１とを有している。   In general, as shown in FIG. 6, the power conversion device 1 includes a DC power source 2 constituted by a solar cell panel, a DC voltage conversion circuit 3 that converts the output voltage of the DC power source 2 into different voltages, and a DC voltage conversion circuit. 3 includes an inverter circuit 4 that converts the DC power converted in step 3 into AC power, and includes an output voltage detection means 10 and an output current detection means 11 of the DC power supply 2 configured by a solar cell panel. .

ここで、電力変換装置１のＭＰＰＴ制御は、図７に示す太陽電池パネルにより構成された直流電源２の電圧―電流特性上の動作点における電圧、電流を測定するとともに該動作点を微小変動させ、図８に示す太陽電池パネルにより構成された直流電源２の電圧―電力特性上の前動作点の出力電力と比較することにより最大出力電力点を追尾させる制御方式（山登り制御方式）が用いられている。   Here, the MPPT control of the power converter 1 measures the voltage and current at the operating point on the voltage-current characteristics of the DC power source 2 constituted by the solar cell panel shown in FIG. 7 and slightly changes the operating point. A control method (mountain climbing control method) is used in which the maximum output power point is tracked by comparing with the output power at the previous operating point on the voltage-power characteristics of the DC power source 2 constituted by the solar cell panel shown in FIG. ing.

また、山登り制御において追従動作の性能向上としては、電圧設定値をＶ１からＶ２へ変化させ、再びＶ１に戻す３つの計測点において、太陽電池パネルにより構成された直流電源２の出力電力を計測し、比較することで、日射の変動を検出するという方式が提案されている。（例えば特許文献１を参照）
また、日射量センサを備え、日射量に対応する最大出力電圧をデータベースとして保持し、その保持された電圧を電圧設定値として制御を行うという方法も提案されている。（例えば特許文献２を参照）
特開平６−３５５５５号公報 特開２０００−１８１５５５号公報 In order to improve the performance of the follow-up operation in the hill-climbing control, the output power of the DC power source 2 constituted by the solar cell panel is measured at three measurement points where the voltage set value is changed from V1 to V2 and returned to V1 again. A method of detecting fluctuations in solar radiation by comparison is proposed. (For example, see Patent Document 1)
In addition, a method has been proposed in which a solar radiation amount sensor is provided, the maximum output voltage corresponding to the solar radiation amount is retained as a database, and the retained voltage is controlled as a voltage setting value. (For example, see Patent Document 2)
JP-A-6-35555 JP 2000-181555 A

しかしながら、上述の山登り制御方式においては、太陽電池パネルにより構成された直流電源の出力電圧を変化させて、検出した直流電源の出力電力の変動に基づき、推測された最大出力電圧（太陽電池パネルの出力電力が最大となる太陽電池パネルの出力電圧）を決定する制御を行っている。しかし、太陽電池パネルにより構成された直流電源の出力電圧を変化させた際に、照度が変化した場合でも、太陽電池パネルにより構成された直流電源の出力電力が変動してしまい、誤った最大出力電圧で動作したり、正確な最大出力電圧に到達するまでに時間がかかって、太陽電池パネルにより構成された直流電源の出力電力が低下するという問題があった。   However, in the above-mentioned hill-climbing control method, the output voltage of the DC power source constituted by the solar cell panel is changed, and the estimated maximum output voltage (of the solar cell panel) is based on the detected variation in the output power of the DC power source. Control is performed to determine the output voltage of the solar battery panel that maximizes the output power. However, when the output voltage of the DC power source configured by the solar cell panel is changed, even if the illuminance changes, the output power of the DC power source configured by the solar cell panel fluctuates, and the incorrect maximum output There is a problem that it takes time to operate with a voltage or to reach an accurate maximum output voltage, and the output power of the DC power source constituted by the solar cell panel is lowered.

また、上記問題点の解決策として特許文献１のように、山登り制御において、電圧設定値をＶ１からＶ２へ変化させ再びＶ１に戻す３つの計測点において太陽電池パネルにより構成された直流電源の出力電力を計測し、比較することで、日射の変動を検出するという方式が提案されているが、制御速度が遅くなり、日射が変動しない場合においても応答速度が悪くなるという問題点がある。   Further, as a solution to the above problem, as in Patent Document 1, in hill-climbing control, the output of a DC power source constituted by a solar cell panel at three measurement points where the voltage set value is changed from V1 to V2 and returned to V1 again. A method of detecting fluctuations in solar radiation by measuring and comparing electric power has been proposed, but there is a problem that the control speed becomes slow and the response speed becomes poor even when the solar radiation does not fluctuate.

また、特許文献２のように、日射量センサを備え、日射量に対応する最大出力電圧をデータベースとして保持し、その保持された電圧を電圧設定値として制御を行うという方法も提案されているが、照度の絶対値を計測する必要があるため、高価な照度計が必要となり、また、太陽電池パネルに影などの外因による出力電力低下があった場合に、誤った形でデータベース化されてしまい、正確な最大出力電圧で動作するように回復するまでに時間かかかってしまうという問題点がある。   In addition, as in Patent Document 2, a method has been proposed in which a solar radiation amount sensor is provided, the maximum output voltage corresponding to the solar radiation amount is retained as a database, and the retained voltage is controlled as a voltage setting value. Because it is necessary to measure the absolute value of illuminance, an expensive illuminometer is necessary, and when the output power is reduced due to external factors such as shadows in the solar panel, it is databased incorrectly. There is a problem that it takes time to recover to operate at an accurate maximum output voltage.

本発明は上述した従来の問題点に鑑みてなされたものであり、制御速度が速く、日射が変動しない場合においても応答速度が悪くならず、高価な照度計などの設置が必要なく、また、太陽電池パネルに影などの外因による出力低下があった場合にも正確な最大出力電圧で動作する、太陽電池パネルにより構成された直流電源の最大出力電力点を効率よく追尾できる電力変換装置を提供することを目的とするものである。   The present invention has been made in view of the above-mentioned conventional problems, the control speed is fast, the response speed does not deteriorate even when the solar radiation does not fluctuate, and there is no need to install an expensive illuminometer, Providing a power converter that can efficiently track the maximum output power point of a DC power supply configured with a solar panel that operates at an accurate maximum output voltage even when the output of the solar panel is reduced due to external factors such as shadows It is intended to do.

本発明の電力変換装置は、太陽電池パネルの発電した直流電力の電圧を昇圧し、さらにこの昇圧された直流電圧を交流電圧に変換し、太陽電池パネルを負荷系統及び商用電力系統に電気的に接続して連系運転を行う電力変換装置であって、前記太陽電池パネルの出力電力を最大にすべく前記太陽電池パネルの出力電圧を制御する出力制御手段と、前記太陽電池パネル周囲の照度変化を検出する画像素子とを備えるともに、前記画像素子が前記太陽電池パネル周囲の照度変化を検出し、この照度変化があった場合、前記出力制御手段は前記太陽電池パネルの出力電力を最大に保つべく、前記太陽電池パネルの出力電圧を変化させない制御を行うことを特徴とする。   The power conversion device of the present invention boosts the voltage of the DC power generated by the solar cell panel, further converts the boosted DC voltage into an AC voltage, and electrically connects the solar cell panel to the load system and the commercial power system. A power conversion device connected to perform interconnection operation, the output control means for controlling the output voltage of the solar cell panel to maximize the output power of the solar cell panel, and the illuminance change around the solar cell panel The image sensor detects a change in illuminance around the solar cell panel, and when there is a change in illuminance, the output control means keeps the output power of the solar cell panel at a maximum. Therefore, the control is performed such that the output voltage of the solar cell panel is not changed.

また、本発明の他の電力変換装置は、前記画像素子が検出する画像面を複数の領域に分割し、照度変化の検出を行うための最も輝度が高く、かつ輝度のばらつきが小さい領域を設定し、この設定された領域の輝度変化により照度変化を検出することを特徴とする。   In another power conversion device of the present invention, the image plane detected by the image element is divided into a plurality of regions, and the region having the highest luminance and the smallest variation in luminance is set for detecting a change in illuminance. In addition, a change in illuminance is detected based on a change in luminance in the set area.

本発明の電力変換装置によれば、太陽電池パネルの発電した直流電力の電圧を昇圧し、さらにこの昇圧された直流電圧を交流電圧に変換し、太陽電池パネルを負荷系統及び商用電力系統に電気的に接続して連系運転を行う電力変換装置であって、前記太陽電池パネルの出力電力を最大にすべく前記太陽電池パネルの出力電圧を制御する出力制御手段と、前記太陽電池パネル周囲の照度変化を検出する画像素子とを備えるともに、前記画像素子が前記太陽電池パネル周囲の照度変化を検出し、この照度変化があった場合、前記出力制御手段は前記太陽電池パネルの出力電力を最大に保つべく、前記太陽電池パネルの出力電圧を変化させない制御を行うことで、いかなる照度変化においても最適な太陽電池パネルからなる直流電源の最大出力電力点が変動することがなく、電力変換装置を確実に最大出力電力点で動作させることが可能となる。   According to the power conversion device of the present invention, the voltage of the DC power generated by the solar cell panel is boosted, and the boosted DC voltage is converted into an AC voltage, and the solar cell panel is electrically connected to the load system and the commercial power system. A power converter for performing continuous operation by connecting to each other, wherein the output control means for controlling the output voltage of the solar cell panel to maximize the output power of the solar cell panel, An image element for detecting a change in illuminance, and the image element detects a change in illuminance around the solar cell panel, and when there is a change in illuminance, the output control means maximizes the output power of the solar cell panel. In order to keep the output voltage of the solar cell panel unchanged, the maximum output power of the DC power source consisting of the optimal solar cell panel for any illuminance change is controlled. There without variation, it is possible to operate at the maximum output power point ensures a power conversion device.

また、画像素子が安価なので、電力変換装置のコストを抑えることができる。   In addition, since the image element is inexpensive, the cost of the power conversion device can be suppressed.

さらに、本発明の他の電力変換装置によれば、前記画像素子が検出する画像面を複数の領域に分割し、照度変化の検出を行うための最も輝度が高く、かつ輝度のばらつきが小さい領域を設定し、この設定された領域の輝度変化により照度変化を検出することで、さらに精度の高い制御を行うことが可能となる。   Further, according to another power conversion device of the present invention, the image plane detected by the image element is divided into a plurality of regions, and the region having the highest luminance and the smallest variation in luminance for detecting a change in illuminance. , And by detecting the change in illuminance based on the change in luminance in the set area, it is possible to perform control with higher accuracy.

以下、図１に従い本発明に係る一実施形態について説明する。   Hereinafter, an embodiment according to the present invention will be described with reference to FIG.

図１は本発明に係る電力変換装置の実施形態の一例を示す概略回路構成図である。   FIG. 1 is a schematic circuit configuration diagram showing an example of an embodiment of a power conversion device according to the present invention.

図１において、太陽電池素子を用いて太陽光を電気エネルギーに変換する太陽電池パネルからなる直流電源２で発電された直流電力は、直流電力を交流電力に変換する電力変換装置１に入力される。電力変換装置１は、太陽電池パネルからなる直流電源２の直流電圧を異なる直流電圧に変換する直流電圧変換回路３と、直流電圧変換回路３にて電圧変換された直流電力を交流電力に変換するインバータ回路４とから構成されており、太陽電池パネルからなる直流電源２の発電電力を交流負荷などに供給もしくは電力会社などの商用系統電力に逆潮流を行う。   In FIG. 1, DC power generated by a DC power source 2 composed of a solar cell panel that converts sunlight into electrical energy using a solar cell element is input to a power converter 1 that converts DC power into AC power. . The power conversion device 1 converts a DC voltage of a DC power source 2 composed of a solar battery panel into a different DC voltage, and converts the DC power converted by the DC voltage conversion circuit 3 into AC power. The inverter circuit 4 is configured to supply the generated power of the DC power source 2 formed of a solar battery panel to an AC load or the like, or to reversely flow the commercial system power of an electric power company or the like.

直流電圧変換回路３はリアクトル５、半導体スイッチ素子６、ダイオード７、平滑コンデンサ８及び半導体スイッチ素子６を制御する出力制御手段（本発明において、出力制御手段は半導体スイッチ素子６のスイッチング周波数などのデューティ比を制御して出力電力を調整する出力制御回路のことである。）９によりチョッパ回路を構成し、電圧変換が行われる。   The DC voltage conversion circuit 3 is an output control means for controlling the reactor 5, the semiconductor switch element 6, the diode 7, the smoothing capacitor 8 and the semiconductor switch element 6 (in the present invention, the output control means is a duty such as the switching frequency of the semiconductor switch element 6). This is an output control circuit that adjusts the output power by controlling the ratio.) The chopper circuit is configured by 9, and voltage conversion is performed.

なお、電圧変換時に電流量も変化するがこちらは特に制御しないものとする。   The amount of current also changes during voltage conversion, but this is not particularly controlled.

また、直流電圧変換回路３には太陽電池パネルからなる直流電源２の出力電圧、出力電流を検出する電圧検出手段１０、電流検出手段１１と、検出された電圧・電流の演算により電力を求める電力計測手段（ＭＰＵ、積算回路などで構成される）１２と、電力変換装置１の内部または外部に設けられた画像素子１３とを有し、太陽電池パネルからなる直流電源２の発電電力が常に最大になるよう制御するための情報を出力制御手段９に送っている。電圧検出手段としては抵抗分割による分圧方式が主流であるが、電流検出手段としてはシャント抵抗や直流電流トランス（ＤＣＣＴ）を用いたり、直流電流のスイッチング時の流れを電流トランス（ＣＴ）で検出して擬似的に測定する方法も用いられる。   In addition, the DC voltage conversion circuit 3 includes a voltage detection means 10 and a current detection means 11 for detecting the output voltage and output current of the DC power source 2 composed of a solar battery panel, and power for obtaining power by calculating the detected voltage / current. It has a measuring means (comprising MPU, integrating circuit, etc.) 12 and an image element 13 provided inside or outside the power converter 1, and the generated power of the DC power source 2 composed of a solar cell panel is always maximum. The information for controlling to become is sent to the output control means 9. The voltage dividing method using resistance division is the mainstream as the voltage detection means, but as the current detection means, a shunt resistor or a direct current transformer (DCCT) is used, or the flow at the time of switching of the direct current is detected by the current transformer (CT). Thus, a pseudo measurement method is also used.

一方、インバータ回路４は複数の半導体スイッチ素子から成るブリッジ回路１４とリアクトルとコンデンサから成るフィルタ回路１５とを有し、直流電圧変換回路３より出力される直流電力を正弦波の商用交流波形に変換し、商用電力系統１６と連系運転を行えるようにしている。これにより照明器具や冷蔵庫などの商用電力負荷へ電力を供給したり、商用電力系統１６へ逆潮流（売電）することができる。   On the other hand, the inverter circuit 4 has a bridge circuit 14 composed of a plurality of semiconductor switch elements and a filter circuit 15 composed of a reactor and a capacitor, and converts the DC power output from the DC voltage conversion circuit 3 into a sine wave commercial AC waveform. However, the system can be connected to the commercial power system 16. As a result, power can be supplied to a commercial power load such as a lighting fixture or a refrigerator, or reverse power flow (sold power) can be made to the commercial power system 16.

次に、電力変換装置１の動作について説明する。直流電圧変換回路３においては、太陽電池パネルからなる直流電源２から直流電力が入力され、出力制御手段９により半導体スイッチ素子６が高速にオン、オフ制御される。半導体スイッチ６のオン時、リアクトル５にはエネルギーが蓄積され、半導体スイッチ６のオフ時に前記エネルギーがダイオード７を通り平滑コンデンサ８部に出力され、太陽電池パネルからなる直流電源２から入力された電圧とは異なる直流電圧に変換することが可能となる。   Next, operation | movement of the power converter device 1 is demonstrated. In the DC voltage conversion circuit 3, DC power is input from a DC power source 2 formed of a solar cell panel, and the semiconductor switch element 6 is controlled on and off at high speed by the output control means 9. When the semiconductor switch 6 is turned on, energy is accumulated in the reactor 5, and when the semiconductor switch 6 is turned off, the energy is output to the smoothing capacitor 8 through the diode 7, and the voltage input from the DC power source 2 composed of a solar cell panel. It becomes possible to convert into a different DC voltage.

なお、半導体スイッチ素子６は変換電圧に応じてパルスのデューティーをコントロールするＰＷＭ方式により制御されている。また、出力制御手段９部は、電圧検出手段１０、電流検出手段１１で検出された太陽電池パネルからなる直流電源２の出力電圧、出力電流値から電力計測手段１２により出力電力を演算し、出力電圧（動作点）を微少に変動させながら太陽電池パネルからなる直流電源２の出力電力が最大になるように制御を行う。   The semiconductor switch element 6 is controlled by a PWM system that controls the duty of the pulse in accordance with the converted voltage. Further, the output control unit 9 calculates the output power by the power measuring unit 12 from the output voltage and output current value of the DC power source 2 composed of the solar cell panel detected by the voltage detecting unit 10 and the current detecting unit 11 and outputs the output power. Control is performed so that the output power of the DC power source 2 composed of the solar battery panel is maximized while slightly changing the voltage (operating point).

一方、インバータ回路４では、ブリッジ回路１４の高速スイッチング動作によるＰＷＭ制御が行われ、ＬＰＦ（ローパスフィルタ）であるフィルタ回路１５を通すことにより、正弦波の交流出力が得られる。出力制御手段９は通常の制御において、太陽電池パネルからなる直流電源２の出力電圧を微小に変化させて電力計測手段１２から得られる出力電力が高くなる方向へ太陽電池パネルからなる直流電源２の出力電圧を制御する。しかし、例えば太陽電池パネルからなる直流電源２の出力電圧を高くした際に日射が低下すると、太陽電池パネルからなる直流電源２の発電量が低下したと判断し、電圧指令値を低くする方向へ制御を行ってしまう。そのため、本発明の電力変換装置においては、画像素子１３により照度変化を検出し、日射変動があった場合には電圧指令値を変動させないように制御を行う。   On the other hand, in the inverter circuit 4, PWM control is performed by the high-speed switching operation of the bridge circuit 14, and a sinusoidal AC output is obtained by passing through a filter circuit 15 that is an LPF (low-pass filter). In normal control, the output control means 9 changes the output voltage of the DC power supply 2 consisting of the solar battery panel minutely so that the output power obtained from the power measuring means 12 increases in the direction of increasing the output power of the DC power supply 2 consisting of the solar battery panel. Control the output voltage. However, for example, if the solar radiation decreases when the output voltage of the DC power source 2 made of a solar cell panel is increased, it is determined that the amount of power generated by the DC power source 2 made of the solar cell panel has decreased, and the voltage command value is lowered. Control. Therefore, in the power conversion device of the present invention, a change in illuminance is detected by the image element 13, and control is performed so as not to change the voltage command value when there is a variation in solar radiation.

図２は本発明に係る照度による太陽光発電制御の実施形態の一例を示す概略構成図、図３の（ａ）、（ｂ）は本発明に係る照度検出の方法の一例を模式的に説明する概念図であり、（ａ）は分割方法、（ｂ）はその具体的事例、図４は本発明に係る相対照度算出の方法の一例を説明するフロー図である。   FIG. 2 is a schematic configuration diagram showing an example of an embodiment of photovoltaic power generation control by illuminance according to the present invention, and FIGS. 3A and 3B schematically illustrate an example of an illuminance detection method according to the present invention. (A) is a dividing method, (b) is a specific example thereof, and FIG. 4 is a flowchart for explaining an example of a relative illuminance calculation method according to the present invention.

図２に示すように、画像素子１３は照度検出部２５と出力制御部２０とから成り、電力変換装置１内に設けてある出力制御手段９のＭＰＰＴ制御部１７へＭＰＰＴ制御を効率よく作動させるための情報を送る。照度検出部２５は画像素子であるＣＣＤカメラ、ＣＭＯＳセンサーなどの照度変化を検出するための装置であり、例えば、後述する図３（ｂ）のような照度状況の変化が判別できる画像情報を採取する。採取された画像情報は出力制御部２０に送られ、解析が行なわれる。まず、画像解析部２１で照度検出部２５から送られてきた図３（ｂ）の映像情報を、例えば図３（ａ）のように照度検出部２５から得られる画像情報を複数の領域（例えば縦３マス×横３マスの９つの領域）に分割しておき、図３（ａ）にある１〜９の画像情報の中から最も照度検知に適した画像領域（最も照度検知に適した画像領域というのは、輝度のばらつきが小さい領域、例えば画像領域５）を選定してメモリ２３に記録する。ここで照度検知に適した画像の判定方法の一例を述べると、まず複数の領域の中で最も輝度が高い部分を有する領域を選定する。そしてその領域の中における最も輝度の高い部分を中心として一定の面積（後述するＭＰＵなどが照度変化を検出するのに必要な画像面積）がほぼその輝度と同じレベル（一例として、例えば１０％以内の差）であれば、その領域の測定ポイントには障害物などがなく、かつ一部の光の反射によるものではないと判断し、以降は領域内の当該ポイントの輝度を照度に換算する方法が挙げられる。このとき、もし輝度が一定の面積無かった場合には、そのポイントは周囲の障害物が風等で揺れたりして正確な変化を読み取れない、もしくは金属物などが太陽光を反射しているだけの局所的な光であると判断し、それ以外の領域で次に輝度の高いところを選定し、同様のフローで判断を行うようにする。そして選定された領域の明るさの相対的な明るさの変化を算出し、照度の変化に変換する相対照度演算部２２によって照度情報として利用可能となる。照度情報はＭＰＰＴ制御部１７に送られて太陽電池パネルからなる直流電源２の出力変動に対する出力制御の追従予測に用いられ、より変換効率の高い太陽光発電が行なわれるようになる。同時に照度情報はメモリ２３に記録され、次に送られてくる画像情報との相対的変化の基準値として用いられる。この制御の流れを図４に示す。   As shown in FIG. 2, the image element 13 includes an illuminance detection unit 25 and an output control unit 20, and efficiently activates MPPT control to the MPPT control unit 17 of the output control means 9 provided in the power conversion device 1. Send information for. The illuminance detection unit 25 is a device for detecting an illuminance change such as a CCD camera or a CMOS sensor as an image element. For example, the illuminance detection unit 25 collects image information that can determine an illuminance change as shown in FIG. To do. The collected image information is sent to the output control unit 20 for analysis. First, the image information of FIG. 3B sent from the illuminance detection unit 25 by the image analysis unit 21 is converted into a plurality of regions (for example, image information obtained from the illuminance detection unit 25 as shown in FIG. 3A, for example). It is divided into 9 areas of 3 vertical and 3 horizontal areas, and the image area most suitable for illuminance detection (image most suitable for illuminance detection) among the image information items 1 to 9 in FIG. As the area, an area having a small luminance variation, for example, an image area 5) is selected and recorded in the memory 23. Here, an example of an image determination method suitable for illuminance detection will be described. First, an area having the highest luminance among a plurality of areas is selected. And a certain area (image area required for MPU or the like to be described later to detect an illuminance change) is almost the same level as the luminance (for example, within 10%, for example) with the highest luminance portion in the region as the center Difference), it is determined that the measurement point in the area is not obstructed and is not due to some light reflections, and thereafter the brightness of the point in the area is converted to illuminance. Is mentioned. At this time, if the luminance does not have a certain area, the point is that the surrounding obstacles are swayed by the wind etc. and the accurate change cannot be read, or the metal object etc. is only reflecting sunlight It is determined that the light is a local light, and the area having the next highest luminance is selected in the other region, and the determination is made in the same flow. Then, a relative brightness change of the brightness of the selected area is calculated, and can be used as illuminance information by the relative illuminance calculation unit 22 that converts the change into illuminance change. The illuminance information is sent to the MPPT control unit 17 to be used for predicting the follow-up of the output control with respect to the output fluctuation of the DC power source 2 composed of the solar battery panel, so that photovoltaic power generation with higher conversion efficiency is performed. At the same time, the illuminance information is recorded in the memory 23 and used as a reference value for relative change with the image information sent next. The flow of this control is shown in FIG.

この画像解析の方法としてはＭＰＵなどによる高度な画像解析を行なって地面などを判定し、その照度変化を検出する方法でもよいが、ＲＧＢ信号を解析し、木や門柱などの色付きの物体を排除し、道路や塀などの太陽光が照射されていると推定される部分の一定面積を選出し、その位置の明るさの変化を相対的に検出するようにするのが好ましい。また、この制御においては、照度の絶対値ではなく相対値で制御ができるため、検出の絶対値精度を必要としない。そのため、安価で普及している画像素子を用いる事が可能となり、例えばＣＣＤを用いた場合には光の情報から輝度信号として諧調の表現度合いであるγ値の変化から用意に照度の相対的な変化を検出することもできる。   As this image analysis method, it is possible to perform advanced image analysis by MPU etc. and determine the ground etc. and detect the change in illuminance, but analyze RGB signal and exclude colored objects such as trees and gate pillars However, it is preferable to select a certain area of a portion estimated to be irradiated with sunlight, such as a road or a fence, and relatively detect a change in brightness at that position. Further, in this control, since the control can be performed using a relative value rather than an absolute value of illuminance, the absolute value accuracy of detection is not required. For this reason, it is possible to use inexpensive and popular image elements. For example, when a CCD is used, the relative illuminance is easily determined from the change in the γ value, which is the degree of expression of gradation as a luminance signal from light information. Changes can also be detected.

なお、画像素子１３を電力変換装置１の外部に設置する場合においては、昨今画像素子を用いた機器が増えているため、インターホンなど他の用途で使用される機器から兼用して照度信号（輝度信号）を得ることで、この装置のためだけの新たな機器の設置をする必要がなく、トータルシステムとしての構成要素を少なくすることができるという利点も挙げられる。   In the case where the image element 13 is installed outside the power conversion device 1, the number of devices using the image element is increasing recently, so that an illuminance signal (brightness) is also shared with devices used for other purposes such as an intercom. By obtaining a signal), it is not necessary to install new equipment only for this apparatus, and there is an advantage that the number of components as a total system can be reduced.

このように画像素子を用いて相対値による制御を行うことにより、如何なる日射状態であっても太陽電池パネルからなる直流電源の最大出力点を正確に追従することが可能であり、誤った最大出力点で動作したり、最大出力点に到達するまでに時間がかかることによって太陽電池パネルからなる直流電源の発電量が低下することのない電力変換装置を提供することが可能となる。   By controlling the relative value using the image element in this way, it is possible to accurately follow the maximum output point of the DC power source consisting of the solar panel in any solar radiation state, and the erroneous maximum output It becomes possible to provide a power conversion device that operates at a point or takes a long time to reach the maximum output point, so that the amount of power generated by a DC power source composed of a solar cell panel does not decrease.

本発明に係る電力変換装置の実施形態の一例を示す概略回路構成図である。It is a schematic circuit block diagram which shows an example of embodiment of the power converter device which concerns on this invention. 本発明に係る照度による太陽光発電制御の実施形態の一例を示す概略構成図である。It is a schematic block diagram which shows an example of embodiment of the solar power generation control by the illumination intensity which concerns on this invention. （ａ）、（ｂ）は本発明に係る照度検出の方法の一例を模式的に説明する概念図であり、（ａ）は分割方法、（ｂ）はその具体的事例である。(A), (b) is a conceptual diagram which illustrates typically an example of the illuminance detection method concerning this invention, (a) is a division | segmentation method, (b) is the specific example. 本発明に係る相対照度算出の方法の一例を説明するフロー図である。It is a flowchart explaining an example of the method of relative illuminance calculation concerning the present invention. 従来の系統連系システムの形態を示す概略説明図である。It is a schematic explanatory drawing which shows the form of the conventional grid connection system. 従来の電力変換装置の形態を示す一例の説明図である。It is explanatory drawing of an example which shows the form of the conventional power converter device. 従来の太陽電池パネルにより構成された直流電源の電圧−電流特性を示す概略グラフである。It is a schematic graph which shows the voltage-current characteristic of the direct-current power source comprised with the conventional solar cell panel. 従来の太陽電池パネルにより構成された直流電源の電圧−電力特性を示す概略グラフである。It is a schematic graph which shows the voltage-power characteristic of the direct-current power source comprised with the conventional solar cell panel.

符号の説明Explanation of symbols

１：電力変換装置
２：太陽電池パネルからなる直流電源
３：直流電圧変換回路
４：インバータ回路
５：リアクトル
６：半導体スイッチ素子
７：ダイオード
８：平滑コンデンサ
９：出力制御手段
１０：電圧検出手段
１１：電流検出手段
１２：電力計測手段
１３：画像素子
１４：ブリッジ回路
１５：フィルタ回路
１６：商用電力系統
１７：ＭＰＰＴ制御部
２０：出力制御部
２１：画像解析部
２２：相対照度演算部
２３：メモリ
２５：照度検出部 1: Power conversion device 2: DC power source comprising a solar cell panel 3: DC voltage conversion circuit 4: Inverter circuit 5: Reactor 6: Semiconductor switch element 7: Diode 8: Smoothing capacitor 9: Output control means 10: Voltage detection means 11 : Current detection unit 12: Power measurement unit 13: Image element 14: Bridge circuit 15: Filter circuit 16: Commercial power system 17: MPPT control unit 20: Output control unit 21: Image analysis unit 22: Relative illuminance calculation unit 23: Memory 25: Illuminance detection unit

Claims (2)

太陽電池パネルの発電した直流電力の電圧を昇圧し、さらにこの昇圧された直流電圧を交流電圧に変換し、太陽電池パネルを負荷系統及び商用電力系統に電気的に接続して連系運転を行う電力変換装置であって、前記太陽電池パネルの出力電力を最大にすべく前記太陽電池パネルの出力電圧を制御する出力制御手段と、前記太陽電池パネル周囲の照度変化を検出する画像素子とを備えるともに、前記画像素子が前記太陽電池パネル周囲の照度変化を検出し、この照度変化があった場合、前記出力制御手段は前記太陽電池パネルの出力電力を最大に保つべく、前記太陽電池パネルの出力電圧を変化させない制御を行うことを特徴とする電力変換装置。 The voltage of the DC power generated by the solar panel is boosted, the boosted DC voltage is converted into an AC voltage, and the solar panel is electrically connected to the load system and the commercial power system to perform interconnection operation. A power conversion device, comprising: output control means for controlling an output voltage of the solar cell panel to maximize the output power of the solar cell panel; and an image element for detecting a change in illuminance around the solar cell panel. In both cases, the image element detects an illuminance change around the solar cell panel, and if there is an illuminance change, the output control means outputs the output of the solar cell panel in order to keep the output power of the solar cell panel maximum. A power converter that performs control without changing voltage. 前記画像素子が検出する画像面を複数の領域に分割し、照度変化の検出を行うための輝度のばらつきが小さい領域を設定し、この設定された領域の輝度変化により照度変化を検出することを特徴とする請求項１に記載の電力変換装置。 The image plane detected by the image element is divided into a plurality of areas, an area with a small variation in luminance for detecting an illuminance change is set, and an illuminance change is detected by the luminance change of the set area. The power converter according to claim 1, wherein
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